Known sowing hearts for pneumatic individual grain sowing assemblies generally consist of two halves, specifically a rear part in which the support of the seed disk and the negative pressure zone are housed, and a front part in which the lower output of the seed container discharges and which itself has a seed storage.
In sowing holes of the seed disk which are adapted to the size of the seed and which are arranged at certain intervals on a circular ring, individual seed grains are received from the seed storage and dropped in a delivery region by interrupting the negative pressure. If the interruption of the negative pressure is not sufficient for dropping, there is a forced stripper at a short distance behind the ideal dropping site.
In order to prepare the seed disk for repeated filling with seed, especially for very small and/or fine seed, the hole in the seed disk is cleaned with overpressure. For this purpose, on the back of the seed disk in the prior art a nozzle is mounted tightly adjoining the seed disk such that the compressed air is blown through each hole in order to remove seed residues from the hole.
On the one hand, the nozzle is subject to wear since it is continually abraded by the rotating seed disk and on the other hand the nozzle is fouled both by impurities in the compressed air and also by abraded matter, seed dressing agents or dirt from the seed disk.
Another disadvantage consists in that the cleaning action of the nozzles from the prior art is unsatisfactory, especially after longer use.